I see, makes sense. I deffaintly will tell them about the spacing out and withdrawing. She did plan for her character to have flashbacks and from the small bit of research I did (which is not a lot) I found out they have triggers that set off the flashbacks. So something very interesting to explore!

Yes haha. PTSD is a lot more complicated than simply flashbacks and what you (commonly) see on TV etc. Be careful not to romanticize or stereotype it! When done correctly, PTSD in characters is compelling and adds a whole new layer to a story.

Hi! I actually have PTSD myself, so I'll try to give some insight on my experience.
So, for me, PTSD manifests as sort of an overlap on my depression, anxiety, and chronic pain. (which are common co-morbid conditions with traumatic events.)
Most of my PTSD presents itself in chronic insomnia and periods of hyper vigilance or disassociation. It's best to think of hypervigiliance as sort of a low-grade paranoid and anxiety mixed.
You're on edge and revved up from no particular reason. People in this state tend to get agitated easy or are prone to panic attacks but there's no loss of touch with reality as would be present in say a manic state. This state leads to a lot of trouble sleeping outside of the occasional nightmares and night terrors that are often already present with PTSD. I think this is the most stereotyped symptom of PTSD in media because it can mix with flashbacks (either emotional ones like recalling similar emotions to your trauma or recalled memories.) resulting in some "over the top" reactions to otherwise normal events. Note, really a small subset of people suffer severely enough to lash out in this state, it's better portrayed as paranoia and avoidance of something that would "set" someone off.
Disassociation is harder to explain in that it is somewhat of a mental disconnect from reality. There are two types of dissociation, de-realization and depersonalization. They both manifest differently but can sometimes manifest together. Derealization almost feels like you're in a dream state. Objects around you and reality just doesn't seem real. Sometimes things can seem foggy and it can be really hard to focus because everything seems just "off." Depersonalization is weirder, some people describe this as an out of body experience but for me personally, I notice it tends to affect my memory the most. Sometimes I'll forget facts about myself, won't recognize my own face in the mirror or my own voice, and it seems like my day is on autopilot and I'm just going through the motions without feeling anything like a robot. These states are often caused by "triggers." I've personally had them after a night of nightmares or running off too little sleep/too much stress.
Speaking of not feeling things, emotional numbness is a common symptom of PTSD as well. It lies on the other end of the spectrum from hypervigilance and feeling "too much at once" in that, it's suddenly hard for you to enjoy anything. This happens most frequently after a traumatic event but for a lot of sufferers, it's a persistent state between episodes of hypervigilance. I think this is where people get the idea of a emotionless "thousand eye stare" in PTSD, but I find that goes along more with flashbacks where someone might appear to stare off space or look momentarily uncomfortable while having one.

Edit: Oh yeah, adding onto this. Since my trauma is from chronic abuse, most of my nightmares are related to the emotions I experienced from that period of my life. They aren't specifically rooted in one singular event, but the "emotional" memory of being exploited and helpless in situations by certain people I know is the same, if that makes sense.
I also suffer from a large degree of memory loss regarding those certain portions of my life and have a bad memory in general. I don't know if it is specifically all related to PTSD but PTSD does affect a lot of people's memory and brain functioning in general, depending on the severity of the traumas experienced.

True! And having a friend write about it gives me the opportunity to learn more about it! I don't actually see a lot about PTSD in movies or anything so I don't know a lot about the stereotypes...

Wow, that's long! Thank you for the information! For the character, it sounds like they have PTSD from killing someone (That's all I know atm). Would that count as something that would cause PTSD? Because of that, they are hesitant to hurt people very badly (enough to cause death) but apparently are chill with fighting? I'll have to ask them for sure... anyways thanks again for the information!

Yeah, flashbacks seem to be an important thing. What phobias would be good? Hm... fear of badly hurting people? Is that a phobia? Would killing someone cause PTSD? Or would it have to be something bigger then that? I actually don't know much about the stereotypes and romanticized people talk about so I'll deffaintly have to do more research into that. Thank you for all the information, I appreciate it (I asked her and she said sure so I guess I'll make a thread aventually)

I feel like most people are scared of hurting other people... but I guess a phobia would be much worse. Kinda like how my mom is scared of spiders even though they are harmless and cute (her freaking out makes me nervous of the spiders lol). Deffaintly something to look into!